Error code C4203

More than likely you have a PDF Owner's manual on the Software install disk. It should have troubleshooting section to help you with this and any future issue. The software may also have a trouble shooting system.
I googled and this seems to be a possible answer:
http://northeastprintsupplies.com/images/FS-C5350DNENSMR1.pdf

To resolve this error, close the printer access door. The printer will not operate while the door/cover is open.
If the error continues even after you close the printer access door, power cycle the printer:

1. Turn off the power (press the On/Off button on the printer).
2. Unplug the printer power cord from the back of the printer.
3. Wait approximately 30 seconds.
4. Plug the printer power cord into the back of the printer.
5. Turn on the power to the printer.

for more help visit https://cbrtechsolutions.net

http://fix-your-printer.blogspot.in/2009/03/canon-lbp2900-error-code-e100-0000.html

Error code E#100, ERR 100 or E100-0000 is a laser scanner unit error.
Solution 1:
Turn off the printer, wait 10 minutes, and then turn it on again.
Solution 2:
Flip open the top of the printer.
Look for a small shutter that holds the laser: carefully force this open with your hands and force the laser out into the center of the tracking cradle.
After you move the laser, unplug the printer for a few minutes.
Plug the printer back in.
Solution 3:
If the same error occurs, it's necessary to contact a service representative.

for other more help visit https://cbrtechsolutions.net

aser scanner unit error.
Turn off the printer, and then turn it on again. If the same error occurs, turn off the printer, then contact the store you purchased the printer, or a service representative. When contacting the service representative, inform them of the error code displayed and symptoms.
Error Code: E100 0000

Laser scanner unit error.
Turn off the printer, and then turn it on again. If the same error occurs, turn off the printer, then contact the store you purchased the printer, or a service representative. When contacting the service representative, inform them of the error code displayed and symptoms.
Error Code: E100 0000

The PCI bus error is detected by the ASIC. - Logic board problem

Hi,

52.x PRINTER ERROR alternates with To continue turn off then on Possible printer control panel error messages 52.0 PRINTER ERROR 52.1 PRINTER ERROR 52.2 PRINTER ERROR Description A temporary printing error occurred. The x can equal one of the following: 0 = Scanner error 1 = Scanner startup error 2 = Scanner rotation error This error can also indicate a problem with the shutter tab on the print cartridge. Action

1. Turn the printer power off, and then turn on the printer power.
2. If the message persists, check the print cartridge for damage.
   1. Verify if the shutter tab on the cartridge is broken or damaged. click on the below link. Shutter tab on the print cartridge
      
3. 1 - Shutter Tab
4. Replace the cartridge if damaged.

If the message continues to persist, then download the printer software based on operating system and reinstall.

HP Laser-Jet 2300d Printer Software


Regards
Chittaranjan

turn off the printer
unplug the power chord at the back of the printer
wait for 5-10 sec.
replug power chord
turn on the printer